roloscot
XS400 Member
Hi,
I am not sure if anyone can help but I am extremely frustrated because I cannot seem to fix this recurring problem with my Yamaha xs400D 1977. The problem is that I have no power above 4000/5000 rpm. When I open up the throttle the bike nearly goes backwards and I get uneven power delivery as well; it feels like that there isn't enough fuel. Below 4000/5000 it seems to run fine and idle isn't too bad either.
This is what I have done so far:
- Two into 1 exhaust
- Cleaned the carburetors out (sent away to do this)
- New main and pilot jets. (2 sizes up from standard)
- Float high set to 28 mm
- Air screws set to 3 turns
- Running Pod filters instead of the standard air filter
- New manifold intakes
- Points adjusted and timing adjusted
- Inlet and Exhaust valves gaps adjusted
- New timer advance
I should also mention that there is a backfire when at idle and one of the cylinders seems to running hotter than the other cylinder.
Any help great appreciated!!!!! Ahhhhhh
Mark.
I am not sure if anyone can help but I am extremely frustrated because I cannot seem to fix this recurring problem with my Yamaha xs400D 1977. The problem is that I have no power above 4000/5000 rpm. When I open up the throttle the bike nearly goes backwards and I get uneven power delivery as well; it feels like that there isn't enough fuel. Below 4000/5000 it seems to run fine and idle isn't too bad either.
This is what I have done so far:
- Two into 1 exhaust
- Cleaned the carburetors out (sent away to do this)
- New main and pilot jets. (2 sizes up from standard)
- Float high set to 28 mm
- Air screws set to 3 turns
- Running Pod filters instead of the standard air filter
- New manifold intakes
- Points adjusted and timing adjusted
- Inlet and Exhaust valves gaps adjusted
- New timer advance
I should also mention that there is a backfire when at idle and one of the cylinders seems to running hotter than the other cylinder.
Any help great appreciated!!!!! Ahhhhhh
Mark.